<template>
    <div>
        <div class="goods">
            <div class="menu-wrapper" ref="menuWrapper">
                <ul>
                    <li class="menu-item" v-for='(good,index) in goods' :key='index'
                        :class='{current:index==currentIndex}' @click='clickMunuItem(index)'>
                        <span class="text bottom-border-1px">
                            <img class="icon" :src="good.icon" v-if='good.icon'>
                            {{good.name}}
                        </span>
                    </li>

                </ul>
            </div>
            <div class="foods-wrapper" ref="foodsWrapper">
                <ul ref='foodsUl'>
                    <li class="food-list-hook" v-for='(good,index) in goods' :key='index'
                        >
                        <h1 class="title">{{good.name}}</h1>
                        <ul>
                            <li class="food-item bottom-border-1px" v-for='(food,index) in good.foods' :key='index'
                                @click='showFood(food)'>
                                <div class="icon">
                                    <img width="57" height="57" :src="food.icon">
                                </div>
                                <div class="content">
                                    <h2 class="name">{{food.name}}</h2>
                                    <p class="desc">{{food.description}}</p>
                                    <div class="extra">
                                        <span class="count">月售{{food.sellCount}} 份</span>
                                        <span>好评率 {{food.rating}}%</span></div>
                                    <div class="price">
                                        <span class="now">￥{{food.price}}</span>
                                        <span class="old" v-if='food.oldPrice'>￥{{food.oldPrice}}</span>
                                    </div>
                                    <div class="cartcontrol-wrapper">
                                        <CartCounter :food='food'/>
                                    </div>
                                </div>
                            </li>
                            
                        </ul>
                    </li>
                </ul>
            </div>
            <ShopCart />
        </div>
        <Food  :food='food' ref='food'/>
    </div>
</template>

<script>
    import BScroll from 'better-scroll'
    import CartCounter from '../../../components/CartCounter/CartCounter.vue'
    import Food from '../../../components/Food/Food.vue'
    import ShopCart from '../../../components/ShopCart/ShopCart.vue'
    import {mapState} from 'vuex'
    export default {
        data(){
            return {
                scrollY:0,//右侧滑动的y轴坐标（滑动过程中实时变化）
                tops:[],//所有右侧分类li的top组成的数组(列表第一次显示后就不再变化)
                food:{}//需要显示的food
            }
        },
        mounted(){
            this.$store.dispatch('getShopGoods',()=>{
                //数据更新后执行
                this.$nextTick(()=>{//列表数据更新显示后执行
                    
                    this._initScroll()
                    this._initTops()
                    
                })
            }) 
        },
        computed:{
            ...mapState(['goods']),
            currentIndex(){//初始和相关数据发生了变化
                //计算得到当前分类的下标
                
                //得到条件
                const {scrollY,tops} = this
                
                //根据条件计算产生一个结果
                const index = tops.findIndex((top,index)=>{
                    //scrollY >= 当前top && scrollY < 下一个top
                    return scrollY >= top && scrollY < tops[index+1]
                })
                
                
                //返回结果
                 return index
            }
        },
        methods:{
            //初始化滚动
            _initScroll(){
               //列表显示之后创建
                    const scrollLeft = new BScroll('.menu-wrapper',{

                        click:true
                    })
                    this.scrollRight = new BScroll('.foods-wrapper',{
                        probeType:2, //因为惯性的滑动不会触发
                        click:true
                    })

                    //给右侧列表绑定scroll监听
                    this.scrollRight.on('scroll',({x,y})=>{
                        this.scrollY = Math.abs(y)
                         console.log(this.scrollY)
                    }) 
                    
                    //给右侧列表绑定scroll结束监听
                    this.scrollRight.on('scrollEnd',({x,y})=>{
                        this.scrollY = Math.abs(y)
                         console.log(this.scrollY)
                    }) 
            },
            //初始化tops
            _initTops(){
                //初始化tops
                const tops = [];
                //收集
                //找到所有分类的Li
                const lis = this.$refs.foodsUl.getElementsByClassName('food-list-hook');
                
                let top=0;
                
                tops.push(top)
                
                Array.prototype.slice.call(lis).forEach(li => {
                    top += li.clientHeight
                    tops.push(top)
                })
                
                //更新数据 
                this.tops=tops
 
                
            },
            clickMunuItem(index){
                console.log(index)
                //使用右侧列表滑动到对应的位置
                //得到目标位置的scrolly
                
                const scrollY = -this.tops[index];
                
                //立即更新scroll(让点击的分类项成为当前分类)
                this.scrollY = scrollY
                
                //平滑滚动右侧列表
                this.scrollRight.scrollTo(0,scrollY,300)
            },
            
            //显示点击的food
            showFood(food){
                //设置food
                this.food=food
                //显示food组件(在父组件中调用子组件对象的方法)
                console.log('aaa')
                this.$refs.food.toggleShow()
            }
        
        },
        components:{
            CartCounter,
            Food,
            ShopCart
        }
    }
</script>

<style lang='stylus' rel='stylesheet/stylus'>
   @import "../../../common/stylus/mixins.styl"
  .goods
    display: flex
    position: absolute
    top: 195px
    bottom: 46px
    width: 100%
    background: #fff;
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          color: $green
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          bottom-border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        bottom-border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>